Nature has inspired mankind for centuries and often led science fiction to become reality. This was once again the case in a scientific experiment that could become Swiss perfection in the renewable energy industry. In this experiment, hybrid solar leaves produce hydrogen steam while absorbing sunlight, proving that mankind can harvest solar fuels with innovative technology inspired by plants’ chemical processes. Should this technology be scaled, it could revolutionize the energy sector.
Seeking new ways to store solar energy
The world is actively striving to keep its carbon footprint as low as possible, with more pioneering renewable energy technologies arising by the day. However, we continue to face challenges with renewable energies, especially storing excess energy. Solar energy, in particular, is one of the renewables that experiences the biggest energy loss due to insufficient storage.
Batteries are typically used, but they must be available on a large scale, which can be costly, require significant space, and result in efficiency loss (especially in long-term storage conditions). Battery production and disposal also pose severe environmental disadvantages. This is why researchers have been seeking new ways to store solar energy.
Enter solar fuels. According to a National Geographic report, solar fuels are key to mitigating climate change, as they can store excess solar energy chemically in a carbon-neutral manner. This is why Swiss researchers have been experimenting with hybrid solar leaves, proving that the answer to our problems was in nature all along.
Hybrid solar leaves may be the answer
A Swiss Federal Institute of Technology (EPFL) research team has created hybrid solar leaves that produce hydrogen steam through photosynthesis. The team’s findings were published in the scientific journal Advanced Materials. The team leader, Kevin Sivula, stated:
“We invented a device that can harvest water from humid air and convert it to hydrogen and oxygen upon sunlight illumination. This work is diretly inspired by the plant photosynthesis that converts carbon dioxide (CO2) from the air to sugars upon sunlight illumination.”
This technology combined semiconductor-based technology with electrodes. The electrodes function as the hybrid solar leaves, and are made from 3D felted glass fiber mesh. Two vital characteristics were kept in mind with the design:
- The electrodes must be porous to maximize water and air contact
- The electrodes must be transparent to maximize solar exposure
Producing hydrogen steam while absorbing sunlight
According to Sivula, creating the electrodes was their greatest challenge. Their technology consists of three primary components, namely:
- A photoanode
- Produces oxygen through water oxidation
- A membrane
- Transports protons to a photocathode to break down protons to hydrogen
- A semiconductor
- Enables the photoelectrochemical reaction to occur to produce hydrogen
Most photoelectrochemical technologies harvest water in a liquid form, whereas the research team used humidity. This method was more practical and would enable the team to scale up their technology more easily. However, before the team can even consider scaling up, they must first focus on enhancing their technology’s hydrogen production performance.
“In this work, we focused on the development of the photocathode part, while the photoanode is currently under investigation in the EU project Sun-to-X. For the final prototype, all the parts, including the photoanode, the membrane, and the photocathode, will be assebled.” – Sivula
In his conclusion, Sivula stated that their research and technology will be vital to addressing the world’s climate change challenges, especially regarding the use of fossil fuels. He added that solar fuels, such as hydrogen, will lower our carbon footprint and enable us to take a vital step forward to becoming a ‘zero-carbon emission economy.’ In the meantime, it seems our fate is still in the hands of batteries, as Central Europe speeds up the fossil fuel transition with solar energy and batteries.
